Ignition system for caseless ammunition

ABSTRACT

Disclosed is an improved ignition for caseless ammunition wherein the primer is positioned in the projectile end of the caseless propellant. This results in an increase in projectile muzzle velocity as well as minimization of the cook-off problem of the weapon while maintaining the advantages of the caseless ammunition system.

Elited States Patent White et al. 5] Apr. 10, 1973 1541 HGNHTHON SYSTEM FOR CASELESS 3,563,177 2/1971 Ritchcy Hun 4r AMMUNHTIQN 3.228.333 1/1966 Phelps 3,018,732 l/l962 Tognola .102/46 X [75] Inventors: Wilmer White, Haddonfield, N.J.;

James F- Kowalick, hh p m, Primary EXaminerRobert F. Stahl a Att0rneyHarry M. Saragovitz, Edward J. Kelly and [73] Assignee: The United States of America as Herbert Bed represented by the Secretary of the [57] ABSTRACT Army Disclosed is an improved ignition for caseless ammuni- [22] Flled' June 1971 tion wherein the primer is positioned in the projectile [21] Appl. No.: 149,305 end of the caseless propellant. This results in an increase in projectile muzzle velocity as well as minimization of the cook-off problem of the weapon U-S- maintaining the advantages of the Caseless am- [5 1 Int. Cl ..F42b munition system [58] Field of Search ..102/38, 46, 70.2, 102/28 [56] References Cited 2 Claims, 2 Drawing Figures UNITED STATES PATENTS 138,679 5/1873 Matt ..lO2/46 IGNITION SYSTEM FOR CASELESS AMMUNITION The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

The invention relates to caseless rounds of ammunition and more particularly to a new and novel means for igniting the molded propellant charge thereof.

Among the advantages of the caseless complete round of ammunition over and above the standard complete round which employs the propellant charge in a metallic cartridge case are saving of weight, ability for the troops in the field to carry more rounds, elimination of the extraction step in the weapon and economy in manufacture. However, with the caseless ammunition concept have arisen several disturbing problems, not the least of these of which is the reliable and efficient ignition of the propellant charge. The problem of reliability is one which can be minimized by good quality control of ammunition and ammunition components production operations. Efficient ignition, however, is still in the early development stages, and when this requirement is coupled with the caseless concept, problems which arise in the cased systems may become extraordinarily complex.

The early caseless ammunition rounds had the primer, which contained the sensitive explosive ingredients necessary for initial energy delivery to the propellant, seated in a conventional manner in the propellant matrix at the breech end thereof. Thus, when ignition occurred, the first propellant combustion products were released at the breech end. This is undesirable from two points of view; first, the propellant gases had to propel not only the projectile itself, but also the remaining unburnt propellant, thus resulting in a lower velocity of the projectile at the muzzle of the weapon; secondly, the propellant gases at the breech end thereof, being very hot, transfer thermal energy to the wall of the weapon adjacent the breech end thereof, thus creating a cook-off hazard for the following caseless rounds when they contact the hot wall. This latter condition cannot be tolerated since it can result in premature ignition of the ammunition in the weapon, rupture of the weapon and loss of personnel. A further, though secondary, disadvantage of this system is that the firing pin of the weapon used to impact-initiate the primer becomes even more eroded than it does in the conventional cased systems or complete rounds, since the erosive gases easily contact the firing pin and therefore erode it.

Accordingly, it is a prime object of the invention to provide a complete round of caseless ammunition which is electrically initiated.

Another object of the invention is a complete round of caseless ammunition which minimizes the cook-off problem in the weapon.

An additional object of the invention is a complete round of caseless ammunition which yields higher projectile muzzle velocity.

A more specific object of the invention is complete round of caseless ammunition having an electric primer affixed in the projectile end of the caseless propellant.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation as well as additional objects and advantages thereof will be best understood from the following description taken in conjunction with the drawings in which:

FIG. 1 is a longitudinal sectional view illustrating the invention; and

FIG. 2 is a longitudinal sectional view through the electrical ignition means.

Referring to the drawings by characters of reference and more particularly to FIG. 1 wherein it) generally indicates in fragmentary cross section, an automatic weapon for firing caseless rounds of ammunition and wherein 11 indicates the barrel, 12 the breech end and 13 a sliding breech block thereof. The sliding breech block 13 may be formed with a central aperture 14 in which is housed an insulator 15 containing a spring urged electrical contactor 16. The caseless round of ammunition consists of the caseless molded propellant 17 having affixed in the front end 18 thereof a projectile 19. In a cavity 20 formed in the base of projectile 19 is affixed an electrical primer means as generally indicated by 21. An insulated electrical conductor 22 has one end connected to the primer means 21, FIG. 2, and runs through the molded propellant 17 to the base or breech end 24 whereat its bare end 23 is bent so as to form in the plane surface of breech end 24 electrical contact means for engagement with the spring urged electrical contactor 16. An electrical source 25 which provides current for activating the electrical primer means 21 has one terminal directly connected to the automatic weapon 10 by conductor means 26 and another terminal connected by means of conductor 27 to the spring urged electrical conductor 16 through switch means 28. Thus, when breech block 13 and switch 28 are in closed position the electrical circuit is completed through electrical primer means 21 since one terminal of primer means 21 is now connected through wire 22 and contactor 23 to a terminal of electrical source 25 and another terminal 29 of primer means 21 is connected through the projectile 19in contact with weapon 10 to another terminal of electrical source 25.

FIG. 2 is a cross section through the electrical primer means 21. A metal cylindrical housing 29 not only comprises means for housing elements of the primer, but also comprises an electrical terminal therefore which as can be seen by reference to FIG. 1 is in contact with projectile 19 in the cavity 20 thereof. An insulator closure means 30 is provided at end 29a of housing 29 and has mounted on a surface thereof facing the interior of the housing an electrically conductive anvil 31 which comprises another electrical terminal of primer means 21. The wire 22 is fed through a bore 31a in the cylindrical wall 37 of housing 29 and is soldered to anvil 31. A second cylindrical metal housing 32 is tightly fitted in housing 29 and has affixed therein at its open end 32a a metal button 33 in electrical contact with anvil 31, but insulated from housing 29 by means of cylindrical insulator 34. A primer charge 35 positioned in housing 32 adjacent button 33 and in contact therewith and the cylindrical wall of housing 32 is retained therein by means of a thin metal cup-shaped closure 36 which is inserted in housing 32 at its end 32b. Thus, it can be seen that when the circuit is closed,

as aforedescribed, a current will flow through anvil 31, button 33, primer charge 35 and housings 32 and 29 whereby primer charge 35 is ignited which in turn ignites caseless propellant 17 at its forward or projectile end 18. Under this condition, the gas from the caseless propellant 17 will push the projectile 19 down barrel 11 while keeping the propellant grain essentially intact, since the pressure from this gas is applied on the propellant towards the breech end. At the same time the thermal transfer to the breech wall of weapon is minimized since the residence time in the area of the breech for any increment of propellant gas is a minimum.

We claim:

1. An ignition improved caseless ammunition adapted to be fired from an automatic weapon comprising in combination a caseless molded propellant, having a projectile positioned in the forward end thereof, and a propellant ignition means mounted in a cavity in the base of the projectile and in direct contact with the forward end of the caseless molded propellant, said propellant ignition means comprising a first metal housing inserted in said cavity and comprising a first electrical terminal for said primer means; an electrical insulator closure affixed in a first end of said first housing adjacent the base of said cavity supporting an anvil comprising a second electrical terminal for said primer means directed inwardly of said first housing; a second metal housing affixed in said first metal housing with the first end thereof adjacent the first end of said first metal housing and supporting a metal button therein electrically insulated therefrom, but in electrical contact with said anvil; an igniter composition in said second housing is electrically conductive contact with said button and said second housing; a thin metal closure means inserted in said second housing at the second end thereof whereby said button and said igniter means are retained therein; and electrical conductor means coupling said anvil through said first housing and caseless propellant with contact means on the breech end of said propellant,

2. A caseless ammunition propellant ignition means adapted for mounting in a base cavity of a projectile and to be in contact with the interfacing caseless propellant comprising, a first metal housing defining a first electrical terminal, an electrical insulator closure affixed to a first end of said first housing adjacent the base of said cavity, an anvil defining a second electrical terminal mounted on said electrical insulator and directed inward of said first housing; a second metal housing affixed in said first metal housing with the first end thereof adjacent the first end of said first metal housing and supporting a metal button therein electrically insulated therefrom, but in electrical contact with said anvil; an igniter composition in said second housing in electrically conductive contact with said button and said second housing; a thin metal closure means inserted in said second housing at the second end thereof whereby said button and said igniter means are retained therein; and electrical conductor means coupling said anvil to the outside of the first metal housing to permit the closure of an electrical circuit through the projectile. 

1. An ignition improved caseless ammunition adapted to be fired from an automatic weapon comprising in combination a caseless molded propellant, having a projectile positioned in the forward end thereof, and a propellant ignition means mounted in a cavity in the base of the projectile and in direct contact with the forward end of the caseless molded propellant, said propellant ignition means comprising a first metal housing inserted in said cavity and comprising a first electrical terminal for said primer means; an electrical insulator closure affixed in a first end of said first housing adjacent the base of said cavity supporting an anvil comprising a second electrical terminal for said primer means directed inwardly of said first housing; a second metal housing affixed in said first metal housing with the first end thereof adjacent the first end of said first metal housing and supporting a metal button therein electrically insulated therefrom, but in electrical contact with said anvil; an igniter composition in said second housing is electrically conductive contact with said button and said second housing; a thin metal closure means inserted in said second housing at the second end thereof whereby said button and said igniter means are retained therein; and electrical conductor means coupling said anvil through said first housing and caseless propellant with contact means on the breech end of said propellant.
 2. A caseless ammunition propellant ignition means adapted for mounting in a base cavity of a projectile and to be in contact with the interfacing caseless propellant comprising, a first metal housing defining a first electrical terminal, an electrical insulator closure affixed to a first end of said first housing adjacent the base of said cavity, an anvil defining a second electrical terminal mounted on said electrical insulator and directed inward of said first housing; a second metal housing affixed in said first metal housing with the first end thereof adjacent the first end of said first metal housing and supporting a metal button therein electrically insulated therefrom, but in electrical contact with said anvil; an igniter composition in said second housing in electrically conductive contact with said button and said second housing; a thin metal closure means inserted in said second housing at the second end thereof whereby said button and said igniter means are retained therein; and electrical conductor means coupling said anvil to the outside of the first metal housing to permit the closure of an electrical circuit through the projectile. 